Armchairs for dental treatment

ABSTRACT

AN ARMCHAIR FOR DENTAL TREATMENT WHICH COMPRISES A FRAME WHICH, IN ADDITION TO THE NORMAL ARTICULATION PERMITTING THE FORWARD AND BACKWARD MOVEMENT OF THE BACKREST PORTION, IS PROVIDED WITH MEANS PERMITTING A SECOND ARTICULATION OF THE BRACKREST PORTION AT RIGHT ANGLES TO THE NORMAL ARTICULATION. THUS THE INVENTIVE CHAIR ALLOWS AN INCLINED LATERAL MOVEMENT OF THE UPPER PART OF THE PATIENT&#39;&#39;S BODY WITHOUT SUBSTANTIALLY ALTERING THE POSITIONING OF THE REST OF HIS BODY.

5, 7 o. M. A. DHQUDAIN 'ARMCHAIRS FOR DENTAL TREATMENT Filed July 1, 1968 United States Patent 3,552,797 ARMCHAIRS FOR DENTAL TREATMENT Olivier Marie Andr dHoudain, Paris, France, assignor to Societe Industrielle de Fabrication et tle Transforma- .tion, Paris, France Filed July 1, 1968, Ser. No. 741,581

Claims priority, application France, Aug. 3, 1967,

Int. Cl. A61g /00 US. Cl. 297355 2 Claims ABSTRACT OF THE DISCLOSURE The present invention has for its object a back for an armchair used in density, such that it inherently permits the dentist to utilize the most favourable means of operating on the patient, both by a special arrangement of its constituent parts with a view to facilitating its use and by an appropriate method of construction of these various parts. The method of operation which is best adapted to the necessities of the dentists work leads to the use of a chair which enables him to limit to the maximum extent the number and the amplitude of his movements during the operation, at the same time constantly ensuring that he has perfect visibility over the field of operation.

In certain positions of working at the side of or facing the patient, it is especially necessary to bring the patients head as close as possible to the dentists body when the latter is working in a sitting position.

The device forming the object of the invention, applied to the back of the chair, satisfies this requirement. It is in fact known that for the purpose of achieving this object, certain devices have been produced, starting from the idea of inclining the whole chair towards the side, giving the chair a rolling movement.

Devices of this kind, while they give the dentist an advantageous convenience of action, none-the-less constitute a costly solution due to the complexity of the mechanism utilized for its production, these mechanisms frequently acting against those of the other movements of the chair. On the other hand, these devices give a patient seated in such a chair, a particularly disagreeable and unstable position, contrary to the idea of relaxation which governs the design of present-day dental equipments, and adversely affecting the satisfactory work of the dentist.

The characteristic feature of the invention consists of acting on the back only of the chair and not on the whole chair, in such manner that in its movement, which may be described as a movement of inclination, it carries with the head and the upper part of the patients body, without thereby substantially changing the position of the remainder of the body.

The chair-back, being adapted in its arrangement to the conditions for which it is intended, is constituted by a frame movable in rotation about an articulation fixed to the seat of the chair. This frame supports the chairback proper, also movable in rotation about an axis at right angles to the articulation of the seat, the chairback carrying the headrest with it in its rotation accord- 3,552,797 Patented Jan. 5, 1971 ing to an appropriate method of construction. This headrest moves longitudinally along the axis of the chair-back proper and is immobilized by the action of the handle with locks it on the frame.

The invention will now be described in greater detail, by way of example With reference to the accompanying drawings, representing one form of construction of a chairback of this kind applied to an equipment for dental use, according to the invention, and in which:

FIG. 1 is a longitudinal section of the dental chair and its back;

FIG. 2 is a cross-section showing a detail of the locking system for the lateral inclination of the back;

FIG. 3 is a transverse section of the parts shown in FIG. 1;

FIG. 4 is an external transverse view of the chair-back in the inclined position.

Referring now ot FIG. 1, it can be seen that the seat of the chair is shown at 1 and that on this seat is articulated laterally the frame 2 which receives the chair-back proper 3 on which the patients back rests. The articulation of the frame 2 on the seat 1 is provided along the axis X-X by a shaft 4 fixed to the frame 2 and capable of rotation by means of ball bearings 5 in a bearing 6 forming part of the seat 1. A chain 7 running on a toothed wheel 8 carried by the shaft 4 is operated in a suitable manner so as to cause the frame 2 to rotate with respect to the seat 1 with an immobilizing or locking system for the control in the chosen position of inclination of the frame 2.

The chair-back proper 3 is pivotally mounted on the frame 2 along the axis Y-Y and, in the construction given by way of example, a shaft 9 fixed to the frame 2 and at right angles to the shaft 4, is mounted in a sleeve 10 which can rotate on the said shaft and carried by the frame 11 of the chair-back 3.

Suitably guided on this frame 11 is arranged the support 12 of the headrest 13, which can be moved by hand longitudinally for the setting in the frame 11 of the chairback 3 by sliding in the extension 10' of the sleeve 10 and at 14 in the frame 11. The headrest support 12 can rotate at the same time as the chair-back 3 rotates about the axis Y-Y', and a shaft 15 riveted at one of its extremities to a trolley 16 and passing through the slot 17 of the support 12 of the headrest can move radially at the same time as the chair-back 3 about the axis YY, being guided in a notch 18 of a plate 19 rigidly fixed to the frame 2, this notch being concentric with the axis Y-Y'.

The trolley 16 carries rollers 20 which roll and are orientated on the plate 19. The shaft 15 is provided at its other extremity with a threaded portion 21 in engagement with the threaded extremity of a lever 22 coupled in articulation at 23 with the extremity of a lever 24, the other extremity of which is pivoted on the lever 25, in turn articulated at 26 on the chair-back 3 and terminating in an operating handle 27.

On the headrest support 12 is articulated, at 28, the

- and 31 by any appropriate device and, for example, by

acting on a small lever 32 which is integral with a thread ed rod 33 passing through the plate 31 and having its threaded extremity screwed into the plate 29.

There has been shown in FIG. 4, the whole assembly of the chair-back and the headrest in a so-called inclined position with respect to the frame 2 with the inclined upper portion of the body of the patient, shown in a diagrammatic manner. The particular profile of the frame 2 shown in FIG. 3 permits the dentist to approach the patient more easily in the front working position.

The operation of the chair for adjustment of the position of the chair-back necessary in order to facilitate the dentists work is as follows:

The movement of extension or retraction of the chairback is effected by rotation of the frame 2 around the axis X-X by acting on th chain 7 which drives the pinion 8 rigidly fixed to the frame 2. The inclination of the chairback 3 With respect to the seat 1 is thus adjusted.

In order to obtain the lateral inclination of the chairback 3 on the frame 2 so as to effect a lateral displacement of the upper part of the patients body, the dentist need only act on the operating handle 27 which rotates the chair-back 3 by means of the shaft 26 about the axis Y-Y, by rotation of the sleeve 10 on the shaft 9. The angular displacement of the handle 27 acts through the levers 22, 23 and 24 to slacken-oif the nut of the lever 22 on the threaded rod 21, which permits the movement of the shaft in the notch 18 of the plate 19. The lat erally inclined adjustment position of the chair-back having been obtained, it is only necessary to release the handle 27 for the locking in the adjusted position to be obtained by screwing the threaded portion of the lever 22 on the threaded extremity 21 of the shaft 15.

The adjustment of the position in height of the head rest support 12 is effected at the same time as the adjustment of the lateral inclination of the chairback, the immobilizing means by the threaded shaft 15 and the threaded portion of the lever 21 acting on the support 12. With regard to the inclination of the headrest 13, this is adjusted by acting on the small lever 32 which, when slackened-off, permits on the one hand the swivel joint 30 to rotate in the receesses of the plates 29 and 31, and on the other hand, by releasing the back-plate 31 on the articulation 20, to cause the whole of this headrest as sembly to rotate on this pivotal axis. This rotation of the lever 32 can be limited to a fraction of a turn so as to provide rapid locking and release.

An examination of the various special features resulting from the mechnaisms described shows that:

A chairback for dental use is especially constituted by a frame articulated on the seat of the chair opposite the front position of the dentist with a view:

On the one hand to achieve the conditions of extension and retraction of this chairback;

On the other hand, by its particular profile, to enable the dentist to improve substantially his conditions of workmg.

This frame is furthermore arranged so as to receive the chairback proper which supports the patient, according to one form of construction, characterized by the fact that this chairback can be made available in rotation about an axis at right angles to the above-mentioned pivotal axis in order to obtain a lateral displacement of the upper part of the patients body, this displacement being caused by a manual action of the dentist, on a handle articulated on the chairback proper, the rotation of which serves in particular to effect the locking or release of this chairback on the frame.

This chairback is further characterized by the fact that it drives in its movement a headrest articulated on a sliding support radial to the axis of rotation, the movement of which enables the dentist to adapt the headrest to the morphology of the patient.

According to an appropriate method of construction this sliding support can be released or locked at the will of the dentist, by acting on the handle.

The headrest is characterized by the fact that it is retained by a support comprising a swivel joint, the hous ing of which is formed in two parts: one is articulated on the sliding support, while the other serves as a locking flange for the headrest and sliding support assembly, by its simultaneous action on the swivel joint and the articulation.

What is claimed is:

1. An armchair for dental treatment comprising a frame having a seat portion, a backrest portion, first means providing an articulated mounting of said backrest portion on said frame about a first axis and permitting forward and backward movement of said backrest portion, second means providing an articulated mounting of said backrest portion about a second axis at right angles to the first axis and permitting said backrest to be inclined laterally independently of said first articulation whereby the head and upper part of the patients body may be moved laterally without substantially altering the position of the remainder of the patients body, manually operated lever means controlling said second articulation means to permit movement of said backrest portion and the locking in place thereof, said backrest portion having a frame with an arcuate slot therein which is concentric with the second articulation axis, a headrest support means mounted to slide along the longitudinal axis of said backrest portion and having a longitudinal slot therein, threaded shaft means passing through said longitudinal slot and movable in said arcuate slot in said frame, lever means connecting said shaft means to said manually operated lever means for immobilizing and freeing said shaft means whereby said headrest support means is simultaneously locked and freed with the lateral control of said backrest portion.

2. An armchair for dental treatment in accordance with claim 1, further comprising a headrest mounted on said headrest support means by swivel joint means having a housing comprising two parts, one of said parts being articulated on said headrest support means and the other serving as a locking means, and means to selectively lock said parts.

References Cited UNITED STATES PATENTS 320,844 6/1885 Burk 297359 FRANCIS K. ZUGEL, Primary Examiner US. Cl. X.R, 

